Many electronic systems include one or more synchronous components that rely on receiving related signals at substantially the same time to maintain proper operating characteristics of the electronic system. A computer system is one example of a synchronous system that may include a multitude of interrelated system components, each designed to perform a particular operation in response to a clock signal. In some cases, data transfer between system components may be synchronized by one or more clock signals originating from a common source. The system components may receive the clock signals through a clocking network, which may include clock generation and distribution circuits.
Phase rotators (interpolators) are commonly used to generate fine phase steps for accurate timing control in various electronic applications such as high-speed serial links and DDR (double data rate) memory applications. Phases generated from a multi-phase PLL or delay line are further interpolated by a bank of phase rotators to provide more (and finer) phases which are then used by calibration mechanisms to park at the right sampling timing.
In some cases, variation in the arrival of a clock signal transition relative to a data signal transition may significantly impact system performance and reliability. For this reason, good clock distribution tends to be very important in the overall performance and reliability of electronic systems. Therefore, it is desirable to have an improved phase rotator.